title: Studies on gamma-aminobutyric acid transport in cobalt experimental epilepsy in the rat.
abstract: Crude brain homogenates and cerebral tissue slices from rats with cobalt metal implanted in right and left cerebral cortices were used to examine high- and low-affinity GABA transport. High-affinity GABA transport was maximally reduced to 34% of controls 7 days after cobalt implantation, a time that coincides with peak seizure activity in this model. Kinetic analysis of high-affinity GABA transport, using brain homogenates, revealed a significant change in Vmax 7 days after cobalt implantation. (Vmax = 446.4 +/- 26.2 pmol/mg prot./min, cobalt, versus 787.8 +/- 67.3, control). An analysis of the low-affinity system revealed no depression of Km or Vmax parameters. Administration of valproic acid at a concentration as high as 1 mM in vitro or a dose of 300 mg/kg in vivo had no effect on high- or low-affinity GABA transport. The results obtained from cobalt-treated rats provide additional evidence for an involvement of GABA in experimental epilepsy.
mesh_terms: D000818:Animals; D001692:Biological Transport; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D003035:Cobalt / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D051381:Rats; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism; D014635:Valproic Acid / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D003035:Cobalt; D005680:gamma-Aminobutyric Acid; D014635:Valproic Acid